/* eslint-disable */
import { saveAs } from 'file-saver'
import XLSX from 'xlsx'

/**
 * 通过表格dom导出Excel
 * @param id 表格ID
 * @param b 开始列数
 * @param e 结束列数
 * @param filename 导出名称
 * @param bookType 导出文件格式
 */
export function exportTableToExcel(id, b, e, filename = 'excel-list', bookType = 'xlsx') {
	const theTable = document.getElementById(id)
	const data = generateArray(theTable, b, e)
	const ws_name = 'SheetJS'
	const wb = XLSX.utils.book_new(),
		ws = sheet_from_array_of_arrays(data)
	/* add worksheet to workbook */
	wb.SheetNames.push(ws_name)
	wb.Sheets[ws_name] = ws
	const wbout = XLSX.write(wb, {
		bookType: bookType,
		bookSST: false,
		type: 'binary'
	})
	saveAs(
		new Blob([s2ab(wbout)], {
			type: 'application/octet-stream'
		}),
		`${filename}.${bookType}`
	)
}

/**
 * 通过JSON数据导出Excel
 * @param multiHeader
 * @param header
 * @param data
 * @param filename
 * @param merges
 * @param autoWidth
 * @param bookType
 */
export function exportJsonToExcel({
	multiHeader = [],
	header,
	data,
	filename = 'excel-list',
	merges = [],
	autoWidth = true,
	bookType = 'xlsx'
} = {}) {
	/* original data */
	data = [...data]
	data.unshift(header)
	for (let i = multiHeader.length - 1; i > -1; i--) {
		data.unshift(multiHeader[i])
	}
	const ws_name = 'SheetJS'
	const wb = XLSX.utils.book_new(),
		ws = sheet_from_array_of_arrays(data)
	if (merges.length > 0) {
		if (!ws['!merges']) {
			ws['!merges'] = []
		}
		merges.forEach((item) => {
			ws['!merges'].push(XLSX.utils.decode_range(item))
		})
	}
	if (autoWidth) {
		/*设置worksheet每列的最大宽度*/
		const colWidth = data.map((row) =>
			row.map((val) => {
				/*先判断是否为null/undefined*/
				if (val == null) {
					return {
						wch: 10
					}
				} else if (val.toString().charCodeAt(0) > 255) {
				/*再判断是否为中文*/
					return {
						wch: val.toString().length * 2
					}
				} else {
					return {
						wch: val.toString().length
					}
				}
			})
		)
		/*以第一行为初始值*/
		let result = colWidth[0]
		for (let i = 1; i < colWidth.length; i++) {
			for (let j = 0; j < colWidth[i].length; j++) {
				if (result[j]['wch'] < colWidth[i][j]['wch']) {
					result[j]['wch'] = colWidth[i][j]['wch']
				}
			}
		}
		ws['!cols'] = result
	}
	/* add worksheet to workbook */
	wb.SheetNames.push(ws_name)
	wb.Sheets[ws_name] = ws
	const wbout = XLSX.write(wb, {
		bookType: bookType,
		bookSST: false,
		type: 'binary'
	})
	saveAs(
		new Blob([s2ab(wbout)], {
			type: 'application/octet-stream'
		}),
		`${filename}.${bookType}`
	)
}

function generateArray(table, b = 0, e) {
	const out = []
	const rows = table.querySelectorAll('tr')
	for (let R = 0; R < rows.length; ++R) {
		const outRow = []
		const row = rows[R]
		let columns = row.querySelectorAll('td')
		if (!(columns && columns.length > 0)) {
			columns = row.querySelectorAll('th')
		}
		let length = (e && e + 1) || columns.length
		for (let C = b; C < length; ++C) {
			const cell = columns[C]
			let cellValue = cell.innerText
			outRow.push(cellValue !== '' ? cellValue : null)
		}
		out.push(outRow)
	}
	return out
}

function datenum(v, date1904) {
	if (date1904) {
		v += 1462
	}
	const epoch = Date.parse(v)
	return (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000)
}

function sheet_from_array_of_arrays(data, opts) {
	const ws = {}
	const range = {
		s: {
			c: 10000000,
			r: 10000000
		},
		e: {
			c: 0,
			r: 0
		}
	}
	for (let R = 0; R != data.length; ++R) {
		for (let C = 0; C != data[R].length; ++C) {
			if (range.s.r > R) {
				range.s.r = R
			}
			if (range.s.c > C) {
				range.s.c = C
			}
			if (range.e.r < R) {
				range.e.r = R
			}
			if (range.e.c < C) {
				range.e.c = C
			}
			const cell = {
				v: data[R][C]
			}
			if (cell.v == null) {
				continue
			}
			const cell_ref = XLSX.utils.encode_cell({
				c: C,
				r: R
			})

			if (typeof cell.v === 'number') {
				cell.t = 'n'
			} else if (typeof cell.v === 'boolean') {
				cell.t = 'b'
			} else if (cell.v instanceof Date) {
				cell.t = 'n'
				cell.z = XLSX.SSF._table[14]
				cell.v = datenum(cell.v)
			} else {
				cell.t = 's'
			}

			ws[cell_ref] = cell
		}
	}
	if (range.s.c < 10000000) {
		ws['!ref'] = XLSX.utils.encode_range(range)
	}
	return ws
}

function s2ab(s) {
	const buf = new ArrayBuffer(s.length)
	const view = new Uint8Array(buf)
	for (let i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xff
	return buf
}
